1. Field of the Invention
The present invention relates to a connector provided with capacitors and more specifically to a connector provided with capacitors, which is not subjected to harmful influence of thermal deformation caused during soldering process. Further, capacitors provided for the connector serve to eliminate (short) relatively high frequency component signals from relatively low frequency component signals passed through the connector terminals.
2. Description of the Prior Art
An example of prior-art connectors provided with capacitors is shown in FIGS. 1(A) to (D). In FIG. 1(A), the prior-art connector comprises a resin connector housing 2, a metallic shield casing 4 fitted to the connector housing 2, a plurality of connector terminals 18 passed through the shield casing 4, and a plurality of cylindrical capacitors 11 soldered between the shield casing 4 and the connector terminal 18, respectively. The connector housing 2 is formed with an internal partition 2A having plural terminal holding projections 2B.
In assembly, the straight connector terminals 18 are pressure-fitted into the central holes 2B-1 of the terminal holding projections 2B, respectively. On the other hand, capacitors 11 are fitted into capacitor holes 4a formed in the shield casing 4 with solid solder 12A interposed between the capacitors 11 and the shield casing 4, respectively as shown in FIG. 1(C), before being passed through a heating furnace (not shown) to solder each outer electrode of each cylindrical capacitor 11 to the shield casing 4 via the melted and solidified solder 12A.
Thereafter, the connector terminals 18 are passed through central holes 11a of the capacitors 11 with solid solder 12B interposed between the connector terminals 18 and the capacitors 11 respectively, until the shield casing 4 is fitted to the connector housing 2, as shown in FIG. 1(B), before being passed through the heating furnace (not shown) to solder each inner electrode of each cylindrical capacitor 11 to each the connector terminal 18 via the melted and solidified solder 12B. Thereafter, the outside portions of the connector terminals are bent into L-shape as shown in FIG. 1(A) without applying internal stress to the solder portions 12A and 12B, to accomplish the assembly of the connector provided with capacitors.
Further, as shown in FIG. 1(B), a ground terminal 13 is fixed to the shield casing 4 perpendicular to the surface of the casing 4. The connector is fixed to a printed circuit board 15 by soldering the ground terminal 13 and ends of terminal pin portions 18a of the terminals 18 to the circuit board 15 via solder 12D and solder 12C, respectively. Further, in FIG. 1(B), terminal tab portions 18c are mated with female terminals (not shown) of a female connector.
In the prior-art connector provided with capacitors as described above, however, since the connector terminals 18 passed through the connector housing 2 are soldered to the shield casing 4 within a soldering furnace and additionally the terminal pin portions 18a of the connector terminals 18 and the ground terminal 13 are soldered to a printed circuit board 15 within a soldering bath arranged on an automatic soldering process line, there exists a problem in that the resin connector housing 2 tends to be deformed relative to the metallic shield casing 4 in three (x, y, z) dimensional directions, in particular in the x direction, as shown by dot-dashed lines in FIG. 1(D), due to a difference in thermal expansion coefficient between the resin connector housing 2 (i.e. the terminal holding portions 2B) and the metallic shield casing 4. Therefore, when the terminal holding portions 2B is deformed, since the rigidity of the connector terminals 18 is higher than that of the capacitor material or the soldering material, cracks CR are easily produced at the solder portions 12A and 12B or the cylindrical capacitor 11 at the worst.
In this connection, it is possible to reduce the thermal stress at the cylindrical capacitor 11 caused by a thermal expansion of the connector terminal 18 by forming a small-diameter portion between the cylindrical capacitor 11 and a bent corner of the connector terminal 18 as disclosed in Japanese Published Unexamined (Kokai) Utility Model Appli. No. 61-79477. However, this method will not reduce the thermal deformation of the connector housing 2 relative to the shield casing 4 due to a difference in thermal expansion coefficient between the resin connector housing 2 and the metallic shield casing 4.